INSULIN Definition Function Importance History Production
Insulin-Insulin is a hormone that regulates theamount of glucose (sugar) in the bloodand is required for the body to functionnormally.-Insulin is produced by cells in thepancreas, called the islets ofLangerhans.
How does Insulin works? Certain cells in the body change the food ingested into energy or blood glucose that cells can use. Every time a person eats, the blood glucose rises. Raised blood glucose triggers the cells in the islets of Langerhans to release the necessary amount of insulin. Insulin allows the blood glucose to be transported from the blood into the cells. Researchers do not yet know exactly how insulin works, but they do know insulin binds to receptors on the cells membrane. This activates a set of transport molecules so that glucose and proteins can enter the cell. The cells can then use the glucose as energy to carry out its functions. Once transported into the cell, the blood glucose level is returned to normal within hours.
Importance of Insulin Without insulin, the blood glucose builds up in the blood and the cells are starved of their energy source. Some of the symptoms that may occur include fatigue, constant infections, blurred eye sight, numbness, tingling in the hands or legs, increased thirst, and slowed healing of bruises or cuts. The cells will begin to use fat, the energy source stored for emergencies. When this happens for too long a time the body produces ketones, chemicals produced by the liver. Ketones can poison and kill cells if they build up in the body over an extended period of time. This can lead to serious illness and coma.
Diabetes People who do not produce the necessary amount of insulin have diabetes. There are two general types of diabetes. The most severe type, known as Type I or juvenile-onset diabetes, is when the body does not produce any insulin. Type II diabetics produce some insulin, but it is either not enough or their cells do not respond normally to insulin. This usually occurs in obese or middle aged and older people.
History250 BC-Apollonius of Memphis coinedthe name "diabetes” meaning "to gothrough".1869- Paul Langerhans, a Germanmedical student, discovered islet cells inthe pancreas1910- Sharpey-Shafer of Edinburghsuggested a single chemical wasmissing from the pancreas. He proposedcalling this chemical "insulin."
1921- Frederick G. Banting and Charles H. Best successfully purified insulin from a dogs pancreas.
In 1919, Moses Barron, a researcher at theUniversity of Minnesota, showed blockage of theduct connecting the two major parts of thepancreas caused shriveling of a second cell type,the acinar. Banting believed that by tying off thepancreatic duct to destroy the acinar cells, hecould preserve the hormone and extract it fromislet cells.In May 1921, Banting and Best tied off pancreaticducts in dogs so the acinar cells would atrophy,then removed the pancreases to extract fluid fromislet cells. Meanwhile, they removed pancreasesfrom other dogs to cause diabetes, then injectedthe islet cell fluid. In January 1922, 14 year-oldLeonard Thompson became the first human to besuccessfully treat-ed for diabetes using insulin.
1936- researchers found a way to make insulinwith a slower release in the blood. They added aprotein found in fish sperm, protamine, whichthe body breaks down slowly. One injectionlasted 36 hours.1950- researchers produced a type of insulinthat acted slightly faster and does not remain inthe bloodstream as long. 1970- researchers began to try and produce aninsulin that more mimicked how the bodysnatural insulin worked: releasing a small amountof insulin all day with surges occurring atmealtimes.
-Researchers continued to improve insulin but the basic production method remained the same for decades. Insulin was extracted from the pancreas of cattle and pigs and purified. The chemical structure of insulin in these animals is only slightly different than human insulin, which is why it functions so well in the human body. (Although some people had negative immune system or allergic reactions.)Early 1980- biotechnology revolutionized insulin synthesis. Researchers had already decoded the chemical structure of insulin in the mid1950s. They soon determined the exact location of the insulin gene at the top of chromosome 11. By 1977, a research team had spliced a rat insulin gene into a bacterium that then produced insulin.
Recombinant DNA technology Joining together of DNA molecules from two different species that are inserted into a host organism to produce new genetic combinations. Genetically modified organism is the product of this experiment. organism whose genome has been engineered in the laboratory in order to favour the expression of desired physiological traits or the production of desired biological products.
Process of Producing Insulin Using Recombinant DNA Technology
First Step (Preparing) The human gene is isolated. The mRNA is taken from the cell of islet of Langerhans. Messenger RNA is a molecule of RNA that encodes a chemical "blueprint" for a protein product. The isolated gene contains the code of the human DNA for the production of insulin. The plasmid DNA of the bacterial cell is taken out of the cell. NOTE: Escherichia coli (E. Coli) bacteria is widely used in producing insulin but yeast may also be used.
Second Step (Cutting) The plasmid DNA of the bacteria is cut out producing plasmid ring which is an empty segment of the DNA. A Restriction Enzyme is an enzyme that cuts DNA at specific recognition nucleotide sequences known as restriction sites. A segment of DNA known as sticky ends.
Third Step (Combining) With the plasmid ring open, the gene obtained from human cell that contains the code of protein responsible for the production of insulin is inserted into the plasmid ring and the ring is closed. The human insulin gene is now combined with the bacterial DNA plasmid.
Fourth Step (Inserting) The resulting DNA is inserted back to the bacteria.
How does the resulting bacteria works? The cells need nutrients in order to grow, divide, and live. While they live, the bacterial cell processes turn on the gene for human insulin and the insulin is produced in the cell. When the bacterial cells reproduce by dividing, the human insulin gene is also reproduced in the newly created cells.
InsulinPresented by: Vince Lowel H. RoseteThis presentation is created by the author whose name is above.All Rights Reserved.No part of this presentation may be reproduced in any form or by anyelectronic or mechanical means, including information storage andretrieval systems, without permission from the author.@2012Duplication, distribution and copying of this presentation is illegal andpunishable by law under copyright infringement.